The ship had approximately 32 sublight engines, which were improvements upon the sublight engine system aboard the two Death Stars.[1] It also possessed at least six fusion reactor complexes at the Starboard, allowing for redundancy and increased damaged resistance.[1]

The Supremacy was large enough to dock eight Resurgent-class Star Destroyers—six externally and two internally. It crewed over 2,225,000 personnel, including officers, stormtroopers, gunners, vehicle engineers, factory workers, technical specialists, and communications staff.[1] It possessed at least 10 military staging areas, each of which could accommodate a full corps of more than 36,000 stormtroopers.[1] The operations decks had floors of workstations filled with highly efficient operators. The vast majority of the crew were Sub-Adults (i.e, too young for active combat deployment), and fully indoctrinated into the First Order myth of a chaotic galaxy requiring a strong, unflinching order to control it.[5]

Because of its role as the First Order's headquarters, not only was the Supremacy able to carry stormtroopers into battle, but it was also capable of harbouring, building, and conducting ship repairs for the First Order Navy in its onboard hangar bays,[2] two of which were large enough to house and repair Resurgent-class Star Destroyers.[1] Additionally, it carried production lines, shipyards, army training grounds and even R&D labs.[7] The Supremacy also acted as one of the premier research labs and factories in the First Order, possessing industrial capabilities rivalling the most productive worlds under the regime's control. Its armored decks housed departments reserved specifically for the conception, research, and approval of new weapons and technology. It also housed well-stocked raw materials reserves, eight durasteel foundries, an asteroid mining complex for harvesting raw materials directly from asteroids fields, as well as state-of-the-art production lines. Training centers were present to indoctrinate young cadets into the military. As it carried all the supply lines, it also could not be cut off from supply lines. Its capabilities were such that its destructive power was comparable to that of a full fleet, its production capabilities comparable to that of a planet, and acted as a testbed for the various military advances of the First Order.[1] It also possessed a detention center near the stern, a commons area, an assembly hall which could accomodate 200,000 personnel, as well as at least 346 laundry rooms. The majority of the crew quarters were placed within the various central "city" blocks of the ship.[1]

It also possessed at least eight droid manufacturing facilities, one of which, P-3, achieved the top rank, as well as a ground vehicle manufacturing zone. The tips of the wings were reserved for top secret labs and dangerous weapons tests, and also possessed communications hubs. The starboard wing possessed a crew transportation causeway with an integrated tram system.[1]

Its main command bridge sat upon a massive structure at the center of the ship, which had a similar design to that of the Mandator IV-class Siege Dreadnought, and to a lesser extent the Resurgent-class Star Destroyer. The bridge had access to displays allowing 360-degree views over everything within the city-scape-like structures on the main "wing" of the destroyer.[2]

The Supremacy used active tracking equipment that allowed it to pursue its targets through hyperspace using a combination of technological advances and brute-force data crunching. The Shipboard Tracking Control Complex boasted the data-shifting power of a planetary intel hub, linking huge computer arrays to data banks loaded with centuries of combat reports and astrogation data. A static hyperspace field generated around the machines accelerated their processing power to unprecedented levels. A target's last known trajectory yielded trillions of potential destinations, but the system could assess these locations with terrifying speed.[1] This capability had its roots from the Tarkin Initiative.[5] The ship, owing to it being the central command ship, forwarding base, and the proverbial brain of the First Order's entire forces, was also entirely self-sufficient, to the extent that its command need not be concerned about supply shortages. In addition, the vessel possessed thousands of heavy turbolasers, anti-ship missile batteries, heavy ion cannons, and tractor beam projectors.[1] The bow of the ship possessed ten heavy turbolaser towers. Only the Death Stars and Starkiller Base rivalled its power.[1] Its communication complex monitored the HoloNet traffic throughout the galaxy to identify trends and weaknesses that the First Order could exploit. As such, they also dispatched orders to various agents operating within both New Republic and independent space.[5]

The ship was built by the First Order at staggering cost within the Unknown Regions to act as the official capital of the First Order at the order of Snoke. Although various officers and allies of the First Order argued for a planet to act as their capital, Snoke insisted on using the Supremacy as the main capital, refusing to designate capital command to a world either under direct First Order control or in the Unknown Regions—at least until the restoration of total galactic control, as part of Snoke's aim to restore and further expand the territory formerly belonging to the Galactic Empire.[1] Armitage Hux agreed with the strategy to keep the capital of the First Order aboard the Supremacy, seeing it as a way to mitigate the risk of it being destroyed in battle when mobile.[6]

Upon completion, the Supremacy was stationed in the galaxy's Unknown Regions to prevent its discovery. During the cold war, Snoke preferred to issue commands from this vessel to his minions.[2] In order to ensure it was not discovered, Snoke also hid it amongst the brightest stars of the Unknown Regions.[5] However, the Resistance nonetheless suspected the existence of the ship, nicknamed "Snoke's Boudoir," and sought to verify its rumored existence among the underworld, even then not realising its gargantuan size.[1] Prior to his defection to the Resistance, FN-2187 spent some time aboard the Supremacy whenever his stationed vessel, the Resurgent-class Star DestroyerFinalizer, was docked with the Supremacy, undertaking patrol routes and basic duties.[5] Regrettably, he was unable to inform the Resistance of its existence prior to the fleet's encounter with it, due to the constraints of time.[6] In the aftermath of the Hosnian Cataclysm, Snoke himself chose to reveal the existence of the ship to the unsuspecting galaxy, determining that the time was both right to reveal himself and declare his intent to pursue the Resistance.[1]

The Supremacy participated in pursuit of the fleeing Resistance fleet. Under the command of General Armitage Hux, the Supremacy followed the fleet, aware that any attempts to jump to hyperspace would be fruitless, since the Supremacy was equipped with hyperspace tracking technology. In consequence, the Supremacy adopted a strategy of attrition, chasing the Resistance until their capital ship depleted its fuel reserves. Utilizing single heavy turbo-laser batteries near the forward hangars, the Supremacy bombarded the Resistance during this chase, immediately destroying a cargo ship, and subsequently a medical frigate and a corvette depleted of fuel.

The Supremacy cut in two due to Vice Admiral Amilyn Holdo's sacrifice

Eventually, the Resistance evacuated their flagship Raddus in transports whereupon Hux ordered the Supremacy to re-target the transports in place of the flagship. While many fleeing transports were destroyed, Hux's failure to realize that Vice AdmiralAmilyn Holdo was preparing a jump to hyperspace aimed directly at the Supremacy left the ship without time to take evasive action. As a result, Hux could watch only in horror as the Raddus severed the starboard wing and further destroying twenty escorting Resurgent-class Star Destroyers in the process.[8] However, due to extensive preparations undertaken by Snoke, a large portion of the First Order's leadership was able to escape.[5] In spite of significant damage to the ship, it nonetheless remained functional. Regardless, the flagship was later deemed to be a lost cause by the First Order, evacuated and scuttled.[6]

The ship was first unveiled via the BB-9E App-Enabled Droid toy by Sphero by going through various areas and collecting data. The initial data erroneously claimed that the length of the Supremacy was over 60km,[2] although the confusion was rectified by Pablo Hidalgo on his Twitter feed where he clarified that the measurement was actually referring to the ship's width via its wingspan.[3]